A team from Italy investigated whether the benefit from oral anticoagulant therapy for idiopathic deep venous thrombosis persists after the regimen is discontinued.
267 patients with a first episode of idiopathic proximal deep venous thrombosis, who had completed 3 months of oral anticoagulant therapy, were enrolled in the study. These were randomly assigned to the discontinuation of oral anticoagulants or to their continuation for 9 additional months.
The primary outcome measure was recurrence of symptomatic, objectively confirmed venous thromboembolism during at least 2 years of follow-up.
The researchers found that, of the 134 patients assigned to continued oral anticoagulant therapy, 21 had a recurrence of venous thromboembolism (15.7%, average follow-up of 37.8 months), compared with 21 of 133 patients assigned to the discontinuation of oral anticoagulant therapy (15.8%, average follow-up of 37.2 months), resulting in a relative risk of 0.99.
|DVT recurrence is not reduced after stopping anticoagulation. |
|New England Journal of Medicine|
During the initial 9 months after randomization, 1 patient had a recurrence while receiving oral anticoagulant therapy (0.7%), as compared with 11 of the patients assigned to the discontinuation of oral anticoagulant therapy (8.3%).
The incidence of recurrence after the discontinuation of treatment was 5.1% per patient-year in patients in whom oral anticoagulant therapy was discontinued after 3 months. This was 5% per patient-year in patients who received an additional 9 months of oral anticoagulant therapy.
None of the recurrences were fatal.
Four patients had non-fatal major bleeding during the extended period of anticoagulant therapy (3%).
Dr Giancarlo Agnelli, of the Università di Perugia, Perugia, concluded on behalf of fellow authors, "In patients with idiopathic deep venous thrombosis, the clinical benefit associated with extending the duration of anticoagulant therapy to one year is not maintained after the therapy is discontinued."